Re: [PATCH v6 4/7] xen/arm: configure dom0less domain for enabling xenstore after boot

[Bertrand Marquis <Bertrand.Marquis@xxxxxxx>]

Hi Julien,

> On 10 May 2022, at 17:35, Julien Grall <julien@xxxxxxx> wrote:
> 
> Hi Rahul,
> 
> On 10/05/2022 17:30, Rahul Singh wrote:
>>> +    rc = evtchn_alloc_unbound(&alloc);
>>> +    if ( rc )
>>> +    {
>>> +        printk("Failed allocating event channel for domain\n");
>>> +        return rc;
>>> +    }
>>> +
>>> +    d->arch.hvm.params[HVM_PARAM_STORE_EVTCHN] = alloc.port;
>>> +
>>> +    return 0;
>>> +}
>>> +
>>> static int __init construct_domU(struct domain *d,
>>>                                  const struct dt_device_node *node)
>>> {
>>> @@ -3214,6 +3243,14 @@ static int __init construct_domU(struct domain *d,
>>>     if ( rc < 0 )
>>>         return rc;
>>> 
>>> +    if ( kinfo.dom0less_enhanced )
>> I think we need to do something like this to fix the error.
>>  if ( hardware_domain && kinfo.dom0less_enhanced )
>> {
>> }
> 
> Is there any use case to use "dom0less_enhanced" without dom0 (or a domain 
> servicing Xenstored)?
> 

Just being curious here but would it even be possible to have non dom0 domain 
servicing xenstored ?

> If not, then I would consider to forbid this case and return an error.

One way or an other we need to solve the crash but if it is forbidden we must 
prevent coming to this step earlier as it means the configuration is wrong.

Cheers
Bertrand

> 
> Cheers,
> 
> -- 
> Julien Grall